(1) Field of the Invention
The present invention relates to an additive for stock feeds, a stock feed containing said additive and a process for the preparation of the additive. When added to livestock feed, the additive of the invention prevents diarrhea in stock and contributes to an increase in the body weight of the stock and the efficient utilization of the feed.
(2) Description of the Prior Art
In recent years, the demand for edible meat has increased, and breeders of stock strongly desire an efficient breeding technique. Today, in the field of stock farming, much attention is paid to the efficient production of the stock, and consequently there is the tendency that the greatest possible number of stock are bred to a limited extent, which often leads to a bad breeding environment. In particular, diarrhea in infant stock during the weaning period has an undesirable influence on their increase in body weight, and in some cases, unfortunately, the stock die. Furthermore, the incomplete development of the stock in their infancy causes the growing period to drag on, so that the efficiency of the stock feed deteriorates and thus profit diminishes.
Accordingly, in order to inhibit the problem of diarrhea and loose passage in the stock, particularly infant stock, stock feeds containing an antibiotic are employed, but the effect of the antibiotic is not considered to be sufficient. In addition, for the prevention of diarrhea, use of various lactic bacteria and/or bifido bacteria has been tried.
Another method has been developed in which an additive prepared by subjecting the starting material milk whey to various treatments is added to the stock feed so as to multiply the number of microorganisms present in the alimentary canal of animals.
The addition of an oligosaccharide to the stock feed has been reported in Japanese Patent Unexamined Publication Nos. 51-118827 and 60-34134.
In Japanese Patent Unexamined Publication No. 52-151787, an agent is disclosed which is prepared by mixing lactose with bifido bacteria. This agent heightens the existence ratio of the bacteria during the storage of the stock feed or in the intestines of the stock.
A conventional technique regarding the stock feed containing an oligosaccharide is disclosed in Japanese Patent Unexamined Publication No. 61-40754.
Some of the products industrially obtained through the above-mentioned methods are on the market, but it is not believed that their effects are sufficient. In order to prevent diarrhea and to efficiently increase the body weight of the stock, there still remain some problems to be solved.
In certain cases, a dosed live bacteria agent is not stably present in the intestines of the stock. In the method of using the oligosaccharide, as disclosed in Japanese Patent Publication No. 60-34134 mentioned above, the manufacturing cost of an additive containing the oligosaccharide is high, which is unprofitable from a commercial viewpoint.
In conclusion, an additive which inhibits diarrhea and effectively increases the weight of the stock has not been developed on a commercial sale.
The inulooligosaccharide disclosed in Japanese Patent Unexamined Publication No. 61-40754 is composed mainly of inulobiose (F.sub.2), inulotriose (F.sub.3), inulotetraose (F.sub.4), inulopentaose (F.sub.5) or inulohexaose (F.sub.6). However, since this inulooligosaccharide is obtained by decomposing inulin with oxalic acid, it mainly contains inulobiose or inulotriose, and does not include many high molecular weight inulosaccharides. Therefore, the inulooligosaccharide disclosed in this publication is not satisfactory for heightening the effectiveness of the stock feed. Furthermore, the raw material from which this inulooligosaccharide is derived is jerusalem artichoke, and, therefore, there is yet another drawback in that the stock do not eat the feed containing it willingly.
Usually, the inulooligosaccharide has excellent characteristics, and for example, it can activate macrophages, develop bifido bacteria, and decrease fat content in the stock. These characteristics are more remarkable in the high molecular weight oligosaccharides than in the low molecular weight oligosaccharides.
It is known that inulin is present in chicory roots. Chicory flakes are utilized as a filler for coffee. Inulin is a polysaccharide in which 35 fructose moieties are linked via a .beta.-2,1 bond, and it has a molecular weight of about 5,400 and carries glucose at the terminal thereof.
The usual inulooligosaccharide can be defined as an oligosaccharide in which 3 to 6 fructose moieties are linked to each other via the .beta.-2,1 bond, and it is generally composed of inulotriose (F.sub.3), inulotetraose (F.sub.4), inulopentaose (F.sub.5) or inulohexaose (F.sub.6).
The inulooligosaccharide may be prepared by a known method, for example, a method of partially decomposing inulin with a dilute acid as described above, or another method of first extracting inulin from a specific plant with warm water, and treating the extracted liquid with an endo-type inulase.
However, these methods are not preferable, because vegetable fiber and trace components which exist in the raw material are lost.
An additive for stock feed which is prepared by directly utilizing decomposition products of a plant containing inulin without removing the vegetable fiber and trace components therefrom is not known. Also, there are not known either a stock feed containing such an additive or a method for preparing this new additive.